Erythropoietin (hereinafter abbreviated as EPO) is a glycoprotein hormone that is essential for erythrocyte hematopoiesis. It is normally secreted from the kidneys and promotes production of erythrocytes by acting on erythrocyte stem cells present in bone marrow. In diseases presenting with a decrease in intrinsic EPO production (such as chronic renal failure), since erythrocyte production decreases and symptoms of anemia are exhibited, treatment is provided in the form of replacement therapy using gene-recombinant human EPO. However, this gene-recombinant human EPO has been indicated as having shortcomings such as being a biological preparation and associated with expensive health care costs, having poor convenience due to being an injection and having antigenicity.
On the other hand, for example, pyrazole derivatives substituted at the 4-position with a carboxy group (see Non Patent Document 1), 3-pyrazolone derivatives substituted at the 4-position with an aromatic heterocyclic group (see Patent Documents 1 to 6), and 4,5-fused 3-pyrazolone derivatives (Patent Document 7), are known to be low molecular weight EPO inducers. 3-pyrazolone derivatives substituted at the 4-position with an alkanoylamino group have not yet been known.